The municipality of Isla Cristina (20,982 inhabitants in 2008; 4,936 ha; municipal website) is located on the Gulf of Cádiz, 45 km west of Huelva and 10 km from the border with Portugal. The fishing port of Isla Cristina, the second biggest Spanish sardine port after Vigo, and the first in Spain for the sales of fresh fish, perpetuates an industry initiated by Catalans in the 18th century. Tourism, favoured by 10 km of sandy beaches, is the other main source of income in Isla Cristina.

Established in 1715 near the mouth of river Guadiana, Catalan merchants were granted in 1724 by King Philip V the concession of an island (isla) where to produce salt fish and to trade it to Catalonia. Each spring, they came back to Andalusia, purchased fish from fishers of Portugal and Andalusia, and salted it; the last shipping of salt fish to Catalonia was scheduled to Novmeber. Every year, the merchants settled the areas of Monte Gordo (Portugal) and La Tuta and La Mojarra, located today in the middle of the Isla Cristina salt marshes (marismas). On 1 November 1755, the tidal wave caused by the Lisbon earthquake destroyed the merchants' headquarters; the next season, the merchants built the first permanent settlement on the island, an enclave watched by José Faneca and his family. Faneca built a well near a fig-tree (higuera), which gave its name to the place, La Figuereta / La Higuerita / La Figarilla.
The enclave was progressively settled by Catalans, Andalusians, Valencians and Portuguese. In 1774-1776, the Marquis of Pombal founded the Royal Town of Santo António as the Portuguese capital of salt fish. To force the fishers of Monte Gordo to move to the new town, the Marquis ordered to burn down their homes, which indeed caused them to settle to La Higuerita. The increase in population and wealth of the island triggerred the interest of the lord of Ayamonte and the town of La Redondela, both claiming jurisdiction (and tax collection) over La Higuerita. Upon the fishers' request, the island was declared property of the Navy by Charles III in April 1788. In 1802, the islanders were granted administrative independence as Real Isla de la Higuerita. Made an ordinary municipality in 1833, the island was renamed Isla Cristina the next year, as a tribute to Regent Queen Maria Cristina.
In the late 19th century, the number of traditional fisheries (almadrabas) dramatically increased on the island. In 1888, the islander Juan Martín Cabet imported modern fishing pots from the USA, while the first sardine canning factory was built in 1892. This started the "Age of Blue Gold", named for blue fish (tuna and sardine). On 12 December 1877, the fading village of La Redondela, with less than 500 inhabitants, was incorporated to Isla Cristina (5,000 inhabitants). Isla Cristina was then ruled by a wealthy oligarchy, who imported several novelties from Catalonia, such as lawn tennis; they also funded the set up of theaters, of a cinema (1907) and of a newspaper (1910). In 1926, the writer and politician Blas Infante Pérez de Vargas (1885-1936), officially considered as the "Father of the Andalusian Nation", who was then a notary in the town, supported the creation of the Ateneo de Isla Cristina, a cultural association modelled on the famous Ateneo de Sevilla. Exporting salt fish to Spain, Italy, Norway, Sweden and France, the islanders modernized their fleet, with sail boats and steamers coexisting for a few decades. On 29 October 1924, King Alfonso XIII granted Isla Cristina with the title of ciudad, a title that required a population of more than 10,000 inhabitants.

The flag (photo, photo) of Isla Cristina, adopted on 12 November 2004 by the Municipal Council and submitted the same day to the Directorate General of the Local Administration, is prescribed by a Decree adopted on 21 December 2004 by the Directorate General of the Local Administration and published on 11 January 2005 in the official gazette of Andalusia, No. 6, p. 38 (text).
The flag is described as follows:

Flag: Rectangular panel, in proportions 11:18, divided in three equal horizontal, parallel stripes perpendicular to the hoist. The first and the third, yellow, the second, central, white with three blue fesses of equal proportions in height and length. Centered and all over, the municipal coat of arms.

The coat of arms of Isla Cristina is prescribed by Decree No. 2,503, adopted on 2 October 1969 by the Spanish Government and published on 28 October 1969 in the Spanish official gazette, No. 258, p. 16,874 (text). This was confirmed by a Decree adopted on 30 November 2004 by the Government of Andalusia and published on 20 December 2004 in the official gazette of Andalusia, No. 246, pp. 28,986-29,002 (text).
The "rehabilitated", "of immemorial use", coat of arms, validated by the Royal Academy of History, is described as follows:

Coat of arms: Argent a well azure a fig tree vert, in base azure three fesses wavy argent two sailboats [of the same]. The shield surmounted with a Royal crown.

The fig tree and the well allude to the original name of the town, Real Isla de la Higuerita, which, itself, recalls that its first settlers dug a well close to a fig tree. The waves represent the sea, recalling that Isla Cristina was once an island, and, subsequently, a peninsula. The boats highlight the industrial vocation of Isla Cristina in relation to the sea.
[Símbolos de las Entidades Locales de Andalucía. Huelva (PDF file)]